Swivel chuck for machining workpieces with a plurality of axes crossing each other

ABSTRACT

A chucking device in which a chuck body has aligned opposed jaws reciprocable toward and away from each other on a common axis and rotatable on the axis. Respective actuators are provided for the jaws to effect the reciprocation of the jaws on the axis. One jaw locks to the chuck body in an outermost position while the actuator therefor develops a greater thrust than the actuator for the other jaw.

United States Patent 1 [111 3,790,181

Scharfen Feb; 5, 1974 SWIVEL CHUCK FOR MACHINING [56] References CitedWORKPIECES WITH A PLURALITY OF I E S T PATENTS AXES CROSSING EACH OTHER3,682,492 8/1972 Scharfen et a] 279/5 Inventor; Hans Scharfen, BuderichGermany 2,643,l32 6/1953 Hunziker et al. 279/4 X [73] Assignee: PaulForkardt Prim ary ExammerFrancis S. Husar KommandltgeseuschaflDusseldorf Attorney, Agent, or FirmWalter Becker Germany [22] Filed:June 6, 1972 57 ABSTRACT [2!] Appl. No.: 260,108 A chucking device inwhich a chuck body has aligned opposed jaws reciprocable toward and awayfrom each other on a common axis and rotatable on the [30] ForeignApphcamm Pnonty Data axis. Respective actuators are provided for thejaws to June 9, 197 1 Germany P 21 28 618.0 effect the reciprocation ofthe jaws on the axis o jaw locks to the chuck body in an outermostposition E while the actuator therefor develops a greater thrust e Q e 1th t f th I 58 Field of Search 279/4, 5 e actua or 6 er Jaw 12 Claims, 2Drawing Figures PATENIEDFEB SIHM 3,790,181

sum 1 0F 2 V PATENTED FEB 51974 SHEET 2 BF 2 SWIVEL CHUCK FOR MACHININGWORKPIECES WITH A PLURALITY OF AXES CROSSING EACH OTHER The presentinvention relates to. a swivel chuck for machining work pieces at aplurality of axes crossing each other, for instance for machining thehousings of armatures, the chuck being provided with a clampingmechanism and a pivoting or swivel mechanism each of which is equippedwith a rotatable clamping jaw which clamping jaws are arranged oppositeto each other and in alignment with each other. The clamping jaw of theclamping mechanism is for clamping and unclamping purposes axiallydisplaceable, and the clamping jaw of the pivoting mechanism is withchucked-in work piece rotatable by means of a pivotable shaft and isadapted to be locked in certain positions.

With a heretofore known swivel chuck of the above described type, thepivoting mechanism comprises a plurality of hydraulic cylinders whichare offset with regard to each other by a portion of the pivoting angle.The pistons pertaining to the hydraulic pressure cylinders are providedwith pushrods and are adapted successively to act upon a multi-corneredbody provided on the pivotable shaft. The pressure cylinders will inthis way bring about not only a pivoting of the rotatable clamping jawsand of the chucked work piece, but will simultaneously bring about alocking thereof.

Although the heretofore known swivel chucks have proved verysatisfactory for work pieces with smaller dimensions, they are not verysuitable for machining large work pieces with dimensions exceeding 1000mm. lf with a swivel chuck for machining such large work pieces theindividual elements thereof were enlarged to a corresponding degree,such chuck would be unfeasibly large. On the other hand, in a chuck bodywhich would be sufficiently strong to withstand the required tensioningand supporting forces, a pivoting mechanism of the described designcould be provided only with such small dimensions that the diameter ofthe pivoting shaft, the radius of the multi-cornered body and the forcesof the pushrods acting thereon would not suffice to lock the work piece,which is supported by the clamping jaw on the pivotable shaft in such arigid manner, especially so rotation-resistant, to the chuck body as itis necessary for a vibration-free machining at its outer end. Thecutting forces occurring during a machining of work pieces with largedimensions will, due to the long lever arm, yield such high torsionmoments that the pushrods acting directly upon the pivotable shaft will,even when enlarging the engaging surface,

not be in the position (due to the short lever arm) to prevent anelastic deformation of the system comprising clamping jaw and workpiece.

It is, therefore, an object of the present invention to provide a swivelor pivotable chuck of the above described type for machining work piecesat a plurality of intercrossing axes which will assure a safe andvibration-free locking of the clamping jaws and which can also beemployed for machining large work pieces.

This object and other objects and advantages of the invention willappear more clearly from the following specification in connection withthe accompanying drawing diagrammatically showing an embodiment of aswivel or pivotable chuck according to the invention, the chuck beingshown in longitudinal section.

The chuck according to the invention is characterized primarily in thatthe clamping jaw of the pivoting mechanism is adapted positively to belocked directly to the body of the pivoting mechanism and together withthe pivotable shaft is axially displaceably journalled in such a waythat by an axial displacement of both clamping jaws and by overcomingthe pressing force of the clamping mechanism the clamping jaw of theclamping mechanism can be unlocked.

According to a further feature of the invention, the positive connectionis effected by two spur gear systems, one of which is arranged on theclamping jaw and the other one of which is arranged on the body of thepivoting mechanism.

The pivotable chuck according to the invention will, in view of thepositive interengagement of the clamping jaw and of the body of theclamping mechanism assure a safe and vibration-free locking which alsowhen machining work pieces of large dimensions will prevent inaccuraciesin the machining. Inasmuch as the locking is effected by the samehydraulic pressure which also produces the pressing force of theclamping piston of the clamping mechanism, it will be assured that thelocking engagement cannot be undone during the working operation. Due tothe employment of spur gears in conformity with the present inventionfor bringing about a positive interengagement, there will be obtainedthe advantage that the pivoting movement can be finely subdivided inconformity with the number of teeth of the spur gears which arepreferably designed as Hirth-serrations. In this connection it isfurthermore possible to select the number of teeth of the gear systemsin conformity with the pitch angles of the work piece and also duringcontinuous operations to maintain the various working positions withhigh precision.

In order to be able to adapt the pivoting movements or locking positionsto the respective work piece to be machined, it is suggested accordingto a further feature of the invention in addition to the clamping jawsalso to make the spur gear teeth on the pivotable body exchangeable.

According to a still further development of the swivel chuck accordingto the invention, the pivotable shaft is adapted to be driven by acontinuous drive, for instance by a hydraulic motor, through theintervention of a worm gear drive. According to a special embodiment ofthe invention, the gear of the transmission is adapted axially to slidedirectly on the pivotable shaft in a non rotatable manner but isslidable in axial direction in order to be able to carry out therequired axial movement necessary for a disengagement.

Finally, it is suggested according to the invention to fasten ahydraulic piston on the pivotable shaft. The displacement force of thishydraulic piston exceeds that exerted upon the clamping jaw of theclamping mechanism, preferably by a hydraulic clamping piston. In thisconnection, different forces may [be realized by differently highpressures or by making the piston surface of the hydraulic piston on thepivotable shaft larger than that of the hydraulic clamping piston sothat the same pressure source can be employed for chucking the workpiece and for unlocking the positive connection.

Further objects and advantages of the present invention will becomeapparent in the drawings and description.

FIG. 1 is a partially sectioned elevational view of a chuck havingfeatures in accordance with the present invention.

FIG. 2 is a cross sectional view taken along the line II II in FIG. 1.

Referring now to the drawing in detail, the pivotable or swivel chuck asillustrated in the drawing comprises a chuck body 1 which is weldedtogether from different parts and has a pot-shaped contour while beingconnected to the spindle of a non-illustrated turning machine. The axisof rotation of the chuck body 1 is designated X-X. Connected to thechuck body 1 are, opposite to each other, a chucking mechanism 2 and apivoting mechanism 3.

A clamping piston 5 is axially displaceably guided in the housing of theclamping mechanism 2. The housing of the clamping mechanism is closed bytwo covers 6 and 7 through which the clamping piston 5 is passed in asealing manner. Rotatably connected to the inner end of the clampingpiston S is a clamping jaw 8 which, in its turn, serves for receiving ajaw 8a. This jaw 80 is formed and designed in conformity with therespective work piece to be machined and is accordingly exchangeablyconnected to the clampingjaw 8. The work piece specifically shown by wayof example in the drawing represents a valve housing.

The second clamping jaw 9 for chucking the work piece 20 is connected toa pivotable shaft 10 which is axially displaceable and is rotatablyjournalled in the housing of the pivoting mechanism by means of twobearing brackets 12 and 13.

In order to obtain an axial displacement of the pivotal shaft 10 whichIn the clamping jaw 9, a hydraulic piston 15 is connected to said shaft10. The rotary movement of shaft 10 is, according to the specificembodiment shown, imparted upon shaft 10 by means of a gear 16 which isdriven by a drive, for instance, a hydraulic motor through theintervention ofa transmission. The gear 16 is keyed to shaft 10. Withthe above mentioned particular design with a gear directly mounted onthe pivotable shaft, said gear is, by means of bearings rings, preventedfrom an axial displacement in the housing ofthe pivoting mechanism. Gear16 is connected to shaft 10 by axial gearing so that these two parts arepositively connected to each other in the direction of rotation whereasan axial displacement of shaft 10 relative to gear 16 is possible whenpiston 15 is acted upon correspondingly. In FIG. 2 there is recognizablein the right part thereof of the housing of the pivoting mechanism 3 inwhich the gear 16 is located as secured upon the pivot shaft 10. Thisgear 16 operates together with a worm pinion or bevel gear 21 which issecured upon a worm shaft 22. This worm shaft 22 has a bore to permitshifting thereof onto the drive stump or stub 23 of a drive 24a which isdriven from a hydraulic motor 24. In order to make possible an axialmovement of the worm shaft 22, the same can be moved to and fro upon thedrive stump or stub 23. The worm shaft 22 is journaled at the upper endthereof in a slide bearing 25 and at the lower end thereof in a needlebearing 26 in a radial direction. Additionally, there occurs ajournaling of the worm shaft 22 by way of two axle bearing means 27 atthe lower end, between which the disc spring package 28 is arranged. Theaxle bearing means 27 are supported upon a cover 29 which is secured bymeans of screws 30 on the housing of the pivoting mechanism 3. In themiddle of the cover 29 there is a stopper 31 which is secured by meansof a screw 32 on the worm shaft 22.

The inventive rotational drive consists of the hydraulic motor 24 and adrive 24a flanged thereon. The gear 16 is joumaled directly upon thepivot shaft 10 and is connected rotationally fixed therewith.

In order to hinder irnpermissibly high tensions in the describedrotational drive which could occur with a displaced meshing of the endface teeth or gear means 9b and 12a, there must be axial shiftingcapability either for the gear 16 upon the pivot shaft 10 or the wormpinion 21 must be axially shiftable with the worm shaft 22. With theillustrated embodiment the entire worm shaft 22 is axially shiftable asrecognizable clearly in FIG. 2.

Between gear 16 and piston 15 in the housing of the pivoting mechanismthere is fastened in a pressure-tight manner an intermediate cover 17through which shaft 10 is passed in a sealed manner. In this way, thepiston 15 separates two cylinder chambers from each other which can bevented or placed under pressure independently of each other.

In order to be able to lock the work piece to be machined in itsrespective position with a high repeat precision and in atorsion-resistant and vibration-free manner on the chuck body 1, theclamping jaw 9 of the pivoting mechanism 3 is, on that side of jaw 9which faces the housing of the pivoting mechanism, provided with spurteeth 9b. These teeth 9b cooperate with spur teeth 12a provided on thebearing bracket 12 of the housing of the pivoting mechanism. In theparticular example shown of the pivotable chuck, both spur gear systems9a and 12a are designed as Hirth-type serrations which, due to theirfine pitch, permit a locking in a great number of positions. Forpurposes of locking, the shaft 10 with the clamping jaw 9 is bysubjecting the piston surface 15b to pressure, moved into theillustrated position. As a result thereof, the spur teeth 9b are firmlypressed into the spur teeth 12a and a precise locating as well as astiff support for the jaw 9 in all directions will be assured.

Prior to chucking a work piece 20, the clamping jaw 9 is held in thethus described and illustrated position but the clamping jaw 8 isretracted. Work piece 20 will then be placed upon the contour jaw 9a,and the clamping piston 15 has its piston surface 5a acted upon by apressure fluid so that the clamping jaw 8 moves toward the work piece 20and holds the same positively and frictionally. The machining of thework piece can be effected in the chucked position.

When the work piece, for instance, an armature housing is to be machinedat an axis which crosses with the present axis, a pivoting of the workpiece about the pivot axis YY is necessary. To this end the positiveinterlock between the clamping jaw 9 and the bearing block 12 has to bereleased. The previously loaded inner surface 15b of the piston 15 isrelieved from the pressure fluid and instead the outer piston surface15a is acted upon by pressure fluid. Since, with the illustratedexample, the piston surface 15a of the hydraulic piston 15 is greaterthan the piston surface 5a of the clamping piston 5, it will beappreciated that when maintaining the chucking force acting upon thework piece, the two clamping jaws 8 and 9 will, together with thechucked work piece 20, be displaced in the direction toward the clampingmechanism 2 so that the two spur gear systems 9a and 12a will disengageeach other.

According to the specific embodiment referred to above, shaft slideswithin the gear 16.

By means of the drive, the gear 16 is turned about a desired angle whilethe work piece 20 is moved into the desired second maching position. Ifnow, the pressure acting upon the piston surface a of the hydraulicpiston 15 is relieved, and the piston surface 15b is again subjected topressure, the clamping jaw 9 moves back to the illustrated position. Inthis connection, the chucking piston 5 which remains further underpressure brings about that also the clamping jaw 8 together with theworkpiece is moved back again. By means of the teeth 9a and 12asimultaneously a locking of the clamping jaw 9 in its new workingposition will occur. This locking is conveyed through the work piecealso upon the clamping jaw 8 of the chucking mechanism 2 so that thechucked work piece can now be machined further.

In view of the fine pitch of the spur teeth 9a and 12a, it is not onlypossible to machine the work pieces at axes crossing each other withlarge angles, for instance with axes crossing each other at 90 or even180, but also crossing angles of a lower even number of degrees arepossible in conformity with the finest of the spur teeth. By means ofthe above mentioned pivotable or swivel chuck, it is possible tomachine, for instance, also the seating surfaces of which slides orvalves in one chucking position with the feeding in and dischargeopenings of the housing of the wedge slide or valve, said seatingsurfaces forming with the wedge slide axis an angle of from 4 to 6.

As will be evident from the above, the described type of locking andunlocking for the clamping jaw 9 not only excels in simplicity precisionand great stiffness, but also assures in a simple manner that theclamping force used for chucking the work piece, for instance, betweenroughing and smoothing, can be reduced at random and independentlythereof can safely remain unchanged during the pivoting operation.

It is, of course, to be understood that the present invention is, by nomeans, limited to the particular showing in the drawing, but alsocomprises any modifications within the scope of the appended claims.

What is claimed is:

1. In a chuck for chucking workpieces, especially workpieces which areto be machined on different axes; a chuck body, first and second jaws insaid body in aligned opposed relation on a chucking axis and supportedfor rotation on said axis, respective actuators in said body connectedto said jaws for moving the jaws toward and away from each other betweenoutermost and innermost end portions on said axis, and cooperatingelements of interengageable locking means on said first jaw and saidbody interengageable in the outermost end position of said first jaw tolock said first jaw against rotation on said body, said elements beingdisengageable in response to movement of said first jaw inwardly fromthe said outermost end position thereof.

2. A chuck according to claim 1 in which said cooperating elements oflocking means comprise tooth means fixed to said body and facing saidfirst jaw and tooth means on said first jaw facing the said tooth meanson said body.

3. A chuck according to claim 1 which includes a shaft rotatable andreciprocable in said body and connected at one end to said first jaw andat the other end to the respective said actuator, and means for drivingsaid shaft in rotation including a gear mounted thereon.

4. A chuck according to claim 3 in which said gear is replaceablymounted on said shaft.

5. A chuck according to claim 3 which includes a m tary drive adaptedfor connection to said gear.

6. A chuck according to claim 5 in which said rotary drive includes afluid motor and a transmission driven thereby, said transmissionincluding a gear meshing with the gear on said shaft.

7. A chuck according to claim 4 in which said gear is slidable on saidshaft but nonrotatable on the shaft.

8. A chuck according to claim 1 in which said actuators comprise apiston for each jaw and a cylinder formed in said body for each piston,a shaft for each jaw having one end connected to the respective jaw andthe other end connected to the respective piston, and means forreversibly supplying fiuid under pressure to said pistons.

9. A chuck according to claim I in which the actuator for said first jawdevelops a greater thrust than the actuator for said second jaw,energization of only the actuator for said second jaw being operable forclamping a workpiece between said jaws, and energization of saidactuator for said first jaw being operable to move said first jawinwardly from locked position thereof even if the actuator for saidsecond jaw is energized at the same time.

10. A chuck according to claim 9 in which each said actuator comprises adouble acting piston connected to the respectivejaw, and the piston forsaid first jaw having a larger effective area than the piston for saidsecond jaw.

11. A chuck according to claim 1 in which said ele ments of lockingmeans comprise: two annular rows of teeth on the said chucking axis andone of said rows on said body and the other of said rows on said firstjaw.

12. A chuck according to claim 11 in which said teeth are in the form offine teeth extending radially to

1. In a chuck for chucking workpieces, especially workpieces which areto be machined on different axes; a chuck body, first and second jaws insaid body in aligned opposed relation on a chucking axis and supportedfor rotation on said axis, respective actuators in said body connectedto said jaws for moving the jaws toward and away from each other betweenoutermost and innermost end portions on said axis, and cooperatingelements of interengageable locking means on said first jaw and saidbody interengageable in the outermost end position of said first jaw tolock said first jaw against rotation on said body, said elements beingdisengageable in response to movement of said first jaw inwardly fromthe said outermost end position thereof.
 2. A chuck according to claim 1in which said cooperating elements of locking means comprise tooth meansfixed to said body and facing said first jaw and tooth means on saidfirst jaw facing the said tooth means on said body.
 3. A chuck accordingto claim 1 which includes a shaft rotatable and reciprocable in saidbody and connected at one end to said first jaw and at the other end tothe respective said actuator, and means for driving said shaft inrotation including a gear mounted thereon.
 4. A chuck according to claim3 in which said gear is replaceably mounted on said shaft.
 5. A chuckaccording to claim 3 which includes a rotary drive adapted forconnection to said gear.
 6. A chuck according to claim 5 in which saidrotary drive includes a fluid motor and a transmission driven thereby,said transmission including a gear meshing with the gear on said shaft.7. A chuck according to claim 4 in which said gear is slidable on saidshaft but nonrotatable on the shaft.
 8. A chuck according to claim 1 inwhich said actuators comprise a piston for each jaw and a cylinderformed in said body for each piston, a shaft for each jaw having one endconnected to the respective jaw and the other end connected to therespective piston, and means for reversibly supplying fluid underpressure to said pistons.
 9. A chuck according to claim 1 in which theactuator for said first jaw develops a greater thrust than the actuatorfor said second jaw, energization of only the actuator for said secondjaw being operable for clamping a workpiece between said jaws, andenergization of said actuator for said first jaw being operable to movesaid first jaw inwardly from locked position thereof even if theactuator for said second jaw is energized at the same time.
 10. A chuckaccording to claim 9 in which each said actuator comprises a doubleacting piston connected to the respective jaw, and the piston for saidfirst jaw having a larger effective area than the piston for said secondjaw.
 11. A chuck according to claim 1 in which said elements of lockingmeans comprise two annular rows of teeth on the said chucking axis andone of said rows on said body and the other of said rows on said firstjaw.
 12. A chuck according to claim 11 in which said teeth are in theform of fine teeth extending radially to said axis.